1. Field of the Invention
The invention relates to a device for separating metal particles from a flow of material consisting of pulverized, granular, or lumpy material to be conveyed.
2. Description of Related Art
By DE-PS 18 09 982, a sorting selector for plastics, in particular for ground material, actuated by a metal detector and comprising a pivotably supported guide body and an actuating element has become known, wherein the channel-like closed guide body, particularly tube section, with its end adjacent to the metal detector, is suspended in a housing receiving the metal detector and, controlled by the metal detector, is alternately held over a trouser leg-like aperture of the housing, respectively. The known device wherein the material to be conveyed passes the selector freely falling is suitable for separating metal particles.
The device has proved itself in practice; owing to its construction, however, it cannot be used with a pneumatic pressure or vacuum conveyor system, wherein very high transport speed, discontinuous transport and transport stops may arise. Further, the device cannot be directly connected to the material connection piece of a processing machine such as a pressing or injection moulding machine, since, in case of a pile-up of the material to be conveyed, the selector becomes inoperative (choked).
This disadvantage has been avoided by German Patent 33 05 268. The device has been specially designed for being connected to the feeder connecting piece of a pressing or injection moulding machine and it separates the material to be conveyed "in portions", either in a good side, or, if metal particles are contained therein, in the bad side of the device. With low transport speeds, the device works excellent. It comprises a closing element which is rigidly coupled to the separating element, which closing element is configured as a slide. The closing element is configured to prevent a pile-up of the material to be conveyed back to the metal detector. The known device, however, is not adapted for such application wherein the material to be conveyed passes the device freely falling.
In contrast to German Patent 33 05 268, German Patent Application 39 29 709 discloses a closing element, in this case a squeezing valve, which is formed independently of the selecting member as a separate construction unit and opened or closed depending on the level of the selecting member so that the material to be conveyed can pass the metal detector freely falling in the filling phase. By means of this device, metal particles can be separated with very great certainty.
In this context, it is referred to the following patents or patent applications referring to devices for separating metal particles and operating with a selector, a metal detector and, if necessary, a closing element: German Patents 9 29 046, 24 56 680, 29 44 192, 31 50 503, 39 31 579, German Patent Applications 38 23 356, 40 17 274, European Patents 202 356, 266 309, U.S. Pat. Nos. 2,045,769, 2,444,751.
It is an object of the invention to provide a device for separating metal particles, which can be easily adapted to different applications.